Many optical systems include mirrors, lenses, or other optical devices that need to be precisely positioned, oriented, or aligned. Often times, a mounting device is used to couple an optical device to a support structure, where the mounting device allows small adjustments to be made to the optical device to help achieve proper positioning, orientation, or alignment. In many cases, a mounting device can support translation of an optical device (movement of the optical device along an adjustment axis), rotation of an optical device (turning of the optical device around an adjustment axis), or both. In some cases, a mounting device supports translation along or rotation around different adjustment axes, meaning the mounting device supports multiple degrees of freedom.
Unfortunately, mounting devices often suffer from a number of shortcomings. For example, some mounting devices provide multiple translational degrees of freedom, but the adjustment axes are not perpendicular to each other. As a result, movement of an optical device along one axis cannot occur without causing movement of the optical device along another axis, which can make it difficult to properly adjust the position of the optical device. Also, some mounting devices provide multiple translational or rotational degrees of freedom without providing locking mechanisms for any or all adjustment axes. In dynamic environments where an optical device may be subjected to load forces (such as shock), the lack of a locking mechanism in each adjustment axis may allow an optical device to move, which can interfere with the operation of a larger optical system.
In one particular approach, a mounting device uses three “push-pulls” (components designed to adjust and hold the space between two structural elements) placed within oversized holes that can operate together to provide translational and rotational adjustments. However, this approach requires the use of special tooling for fine translational adjustments, which tends to be clumsy and ineffective. The tooling also sometimes creates over-constraint and lockdown problems, such as stress-induced distortions of an optical device. Moreover, in order to allow use in a dynamic environment, this approach requires the use of potting (material that hardens after injection into the oversized holes) once the adjustments are finalized, which prevents further adjustments from being made to the optical device's position, orientation, or alignment. In addition, this approach requires multiple knobs to be adjusted in order to make a single translational adjustment to an optical device, which makes it difficult to adjust the position of the optical device along a single adjustment axis.